/Engine/Source/Runtime/SlateCore/Public/Layout/BasicLayoutWidgetSlot.h
typedef typename std::conditional< InPaddingInvalidationReason==EInvalidateWidgetReason::None,::[SlateAttributePrivate::FSlateAttributeNoInvalidationReason](API\Runtime\SlateCore\Types\Attributes\FSlateAttributeNoInvalidationRea-), TSlateAttributeInvalidationReason< InPaddingInvalidationReason >>::type SlotPaddingInvalidationType